Slurry, defined as fluid containing insoluble matter such as sand, gravel or other solid material, is sometimes transported from one location to another through the use of a pump. Often the pump has a pump housing containing an internally mounted, rotating rotor or impeller which engages slurry entering the pump and drives the slurry to exit to the pump.
One problem that arose in the past when pumping slurry using some conventional pumping apparatus is that the insoluble matter in the slurry sometimes caused excessive wear and damage to the pumping apparatus through contact with the parts of the pumping apparatus, especially the impeller. To address this problem, some pumps were designed to reduce the amount of contact between the slurry and the parts of the pump. In general, these slurry pumps have an empty space, or fluid chamber, in the pump housing that permits slurry to travel from an input passage to the pump housing to an output passage from the pump housing while reducing contact between the slurry and the parts of the pump. In slurry pumps, the rotating impeller is typically located adjacent to and substantially outside the fluid chamber. By forming a fluid chamber in the pump housing adjacent the impeller, the impeller can move the slurry entering the pump through the input passage toward the output passage while reducing contact between the slurry and the impeller.
Many conventional slurry pumps having a fluid chamber designed to reduce contact between the pump and the slurry are versatile in that, in addition to pumping slurry, they may be used to pump fluid containing little or no insoluble matter. Since slurry pumps can be used to pump either slurry or fluid, the term "fluid" as used herein will include fluid with or without insoluble matter.
One problem encountered with some conventional slurry pumps that have a fluid chamber is that irregularities or deviations in the fluid flowing through the pump housing from the input passage to the output passage may cause the pump to lose head or prime. These irregularities may be caused by solid matter or gas bubbles in the fluid. When irregularities cause the pump to lose prime, the pump no longer moves fluid through the pump housing. To begin pumping again, the pump must be reprimed, which can be a time consuming process.
Another problem encountered with some conventional slurry pumps is that the output flow of fluid from the pump is not uniform and pulsates. A pulsating fluid flow from the output passage produces undesirable pulsating reactionary forces on the output passage that may make the output passage difficult to control.
It is clear that there has existed a long and unfilled need in the prior art for a slurry pump that solves these and other problems associated with the prior art.